In lubricants for mechanical systems, both the first appearance and the ongoing presence of metal particulates can be an indication of impending failure. Lubricant composition may be especially revealing in lubrication fluids in some mechanical systems such as gear boxes, transmissions, hydraulic systems, or engines. When such systems are in aircraft, flight safety requirements dictate that regular and thorough oil analysis be conducted. To assist in detecting the presence of metals in such systems, and in particular, the presence of metal particulates, detectors have been developed. Such detectors are commonly called chip detectors, since they detect metal chips. Many chip detectors are designed to allow flow of lubricant through, or around, a portion of the detector. Chip detectors include sensors for detecting the presence of chips, and provide an indication upon first appearance of, and during ongoing presence of, metal particulates. Chip detectors provide a significant benefit in assisting maintenance and operations personnel in averting potential catastrophic failure. However, there remains a need to obtain lubricant samples to observe metal wear rates in mechanical parts via the metal content of spent lubricants (whether in particulate form, or in dissolved form, or in a complexed form, or in other form), or to verify the absence of metal particulates, or in the case when activation of a chip detector alarm has occurred, to verify the presence of metal particulates. In other words, in addition to observation of wear rates in mechanical equipment, an important reason for sampling is to verify the correct operation of chip detectors. Thus, many aircraft lubricant systems include self-closing valves that facilitate frequent lubricant sampling. Resulting lubricant samples are sent to oil analysis laboratories. Based on the report of a particular lubricant sample, further action may be taken, as appropriate.
Unfortunately, taking samples from many self-closing valves continues to be a messy and time consuming job. Often, makeshift equipment is utilized. For example, in military field operations, plastic tubing intended for medical applications may be cut up in lengths suitable for extraction of oil samples. This is time consuming, and uses up expensive supplies intended for other uses. And, regardless of the sophistication of such improvised measures, quite often a messy and potentially dangerous oil release occurs, either on to aircraft parts, some of which may be hard to reach or to clean, or into the adjacent environment. Consequently, there remains a significant and as yet unmet need for a simple, reliable, low cost, and effective oil sampling device which is especially adapted for use with quick-release valves, as often found in aircraft chip detectors.
The foregoing figures, being merely exemplary, contain various elements that may be present or omitted from actual embodiments which may be implemented, depending upon the circumstances. Further, similar parts may be denoted with similar symbols, but utilizing a “prime” symbol as a suffix—“′”—and these shall be considered the functional equivalent of similar parts without such prime suffix symbols thereafter, as such nomenclatures is utilized in order to avoid unnecessary duplicate explanation of components or of the function thereof, especially as utilized shown in FIG. 6, for example. An attempt has been made to draw the figures in a way that illustrates at least those elements that are significant for an understanding of the various embodiments and aspects of the invention. However, various other elements of a suitable liquid sampling apparatus may be utilized in order to provide a versatile liquid sampling apparatus for reliably extracting a lubricant sample from mechanical apparatus while minimizing or eliminating leakage of lubricant, in accordance with the teachings hereof and the claims set forth hereinbelow.